基于起伏地形的SAR森林二次散射有效路径计算

提出了一种基于起伏地形的SAR森林二次散射有效路径计算方法. 采用大尺度面元拟合来描述地表的坡度变化,通过对散射粒子与大尺度面元的二次散射进行条件遍历,充分考虑了地表具有大尺度起伏特征时森林雷达二次散射可能不存在或存在多条二次散射有效路径的情况. 为了提高计算效率,一方面限定了遍历的面元范围,另一方面将森林场景划分为三维网格,用网格中心处有效路径的遍历结果作为网格内散射粒子的二次遍历条件. 计算机仿真给出了在分形模拟地形和实测DEM数据下二次散射有效路径的计算实例,并与单一坡度倾斜地表模型的计算结果进行了对比,结果表明,该方法能够有效地表征地形起伏情况下森林的雷达二次散射特征. 

Effective Path Computation of SAR Double Bounce Scattering from Trees Based on Undulating Terrain

Computation method for effective path of SAR double bounce scattering from trees based on undulating terrain is presented. The large-scale elements of surface fitting are used to describe the variation of surface slope. Through conditional searching of scattering particles and double bounce scattering, the situation that there may be none or many effective paths of double bounce scattering from trees when the terrain is undulating with large-scale feature is fully considered. In order to improve the computation efficiency, the searching area is restricted and the forest stand is divided into three-dimension grids. The conditional searching for the scattering particles in a certain grid is based on the effective path searching results at the center of the grid. Example simulation of double bounce scattering effective path has been demonstrated based on fractal DEM and measured DEM. Results indicate that, compared with the result based on tilted ground with single slope, the proposed method could effectively characterize the double bounce scattering from trees based on undulating terrain.